It could have been due to the recent legalization of online poker in Nevada, or simply the lure of winning a seven-figure first prize for a minimal investment.

Maybe they just came to see the Frisbee-catching dogs.

Whatever the reason, a record number of players entered the “Millionaire Maker” tournament Saturday during the World Series of Poker at the Rio Convention Center.

The $1,500 buy-in Single Re-Entry No-Limit Hold ’em tournament, featuring a guaranteed $1 million to the winner, officially had 7,977 entrants when registration closed late Saturday.

The prize pool is in excess of $10.7 million.

“Poker has long had its championship in the Main Event, but now the WSOP has a bona fide kickoff spectacular,” WSOP executive director Ty Stewart said.

The 2014 “Millionaire Maker” is the second-largest tournament in WSOP history behind only the 2006 Main Event, which had 8,773 players at the Rio.

Seth Palansky, vice president of corporate communications for Caesars Interactive Entertainment, wrote in an email that Saturday “will go down as the biggest one-day starting event in the history of the game of live poker.”

Last year’s inaugural “Millionaire Maker” tournament set a record for a non-Main Event field with 6,343 participants, and winner Benny Chen took home nearly $1.2 million. This year’s champion will get more than $1.3 million thanks to the massive field.

“Our customers really like money. So, a seven-figure payday for a relatively modest wager is tough to ignore,” Stewart said. “The eight-figure guarantee for the Main Event has people buzzing. It’s going to be a great summer, and I think we have created two strong bookends that drive a lot of interest in the city and the game.”

The final table for the “Millionaire Maker” was originally scheduled to start at 1 p.m. Monday, but Palansky confirmed it now will take at least four days to complete the tournament.

A minimum of 12 players will earn a six-figure payout in the “Millionaire Maker” and the winner cashes more than 860 times their $1,500 investment.

“Buzz is high again,” Stewart said. “Vegas has rebounded, and there’s plenty of optimism that the 2014 WSOP is shaping up to enrich poker players like never before.”

Here are the payouts for the 2014 “Millionaire Maker”:

1st: $1.3 million+ (will end up in the Top 20 all time in terms of payouts in a WSOP event)